Lubricating grease composition



Jan. 13, 1953 MOORE 2,625,510

LUBRICATING GREASE COMPOSITION Filed Oct. 25, 1951 5 Sada Base Grease Conhalninq 37.0 510 oxidized Edeleanu E Exi-r-am- Derived -Fr-om Go 46 mo sus aiuo'F Bulk (3 Sada base Grease ConM'l m 2 5', Non-Oxidized Ede|aan:4 F Ex1'rac1' Derived fi-am GO 2 19 sus ai- 'Llo'F Bulk n'lsfillara. 28o I 1:10

o '2. 4 a 8 1o WeeKs Si'oraqe lnven+or= Rabat-1' J. Moore.

'5 4 4 Mir/h His Mar-n61.)

Patented Jan. 13, 1953 LUBRICATING GREASE COMPOSITION Robert J. Moore, Oakland, Calif., assignor to Shell Development Company, Emeryville, Califl, a

corporation of Delaware Application October 25, 1951, Serial No. 253,110

20 Claims. 1

This invention relates to improved lubricating grease compositions. More particularly, it pertains to novel grease compositions which resist bleeding and age-hardening and which possess outstanding mechanical stability and thermal reversibility.

It is well established that oxidation has a profound deteriorating effect upon lubricants and lubricating compositions. The rapidity of this deterioration varies with difi'erent lubricants and depends in part upon the source of the base oil, the presence and nature of additives therein, as well as on the conditions to which the lubricant is exposed. Once oxidation has started in a lubricant, the deterioration caused thereby appears to be an autocatalytic phenomenon, resulting in further deterioration of the lubricant.

Bleeding is a phenomenon frequently encountered in grease compositions, this bleeding being manifested by an undesirable separation of the soap and lubricant, comprising the grease mixture, into fluid oil and a portion richer in soap. This action has also been termed syneresis, and it is thought to be due to changes occasioned by some instability in the soap-hydrocarbon structure.

Generally, to inhibit bleeding and to improve the texture of greases, special precautionary measures are taken, such as employing slow or rapid means of cooling, or extensively working the grease in special homogenizers, e. g. the Cornell homogenizer, and the like. Such procedures are usually time consuming and add greatly to the cost of the grease. Other ways of producing stable, non-bleeding greases have been attempted by either reducing the soap content generally to less than about 5% by weight or by increasing the soap content to a high level. These methods of stabilizing greases against bleedin have also proved to be unsatisfactory because in the case of reducing the soap content to less than 5%, such greases become limited in their use due to the low soap content, while increasing the soap content to a maximum makes the grease too costly and such products generally possess an undesired consistency.

The cause or causes of age-hardening of greases is not understood at present. It is believed to be caused by the soap fibers in storage tending to recrystallize at points of contact to form a more rigid matrix and thus give rise to increased consistency. Such hardening is extremely undesirable for it introduces numerous lubricating difliculties. such as in pumping equipment, and the like. 1

It is an object of this invention to produce greases which are resistant to bleeding and agehardening. It is a further object of this invention to produce greases by known means, said greases containing additives which prevent agehardening and bleeding of said greases. Furthermore, it is an object of this invention to produce general all-purpose non-bleeding, non-agehardening greases containing a minimum amount of soap. Still another object of this invention is to provide a method of making and cooling greases either in a batch or continuous process whereby mechanically stable, non-bleeding products are produced which are resistant to agehardening.

Now it has been found that the above and other objects of this invention may be attained by adding to a grease composition a minor amount (but sufiicient to inhibit oxidation, bleeding and age-hardening) of an oxidized petroleum hydrocarbon rich in aromatics having an aniline point of 75 C. or less, and preferably having an aniline point of C. or less, preferably between 25 and 65 F. Mixtures of said oxidized aromatic-rich petroleum hydrocarbons and/or certain specific fractions thereof, such as nitrogenous and/or sulfurous fractions, can be used also and derivatives thereof. These highly aromatic hydrocarbons may be obtained from various petroleum stocks rich in aromatics by selective solvent treatment, the solvents used in the treatment of a suitable petroleum stock being adapted to segregate the aromatic constituents from the non-aromatic constituents present in the petroleum stock. Suitable solvents may be represented by sulfur dioxide, phenol, furfural, nitrobenzene, cresol, aniline, beta,beta-dichloro-diethyl ether and the like. Petroleum hydrocarbons which are particularly suitable for treatment with the above types of solvents and mixtures thereof are those in the lubricating oil ranges, namely petroleum fractions boiling above about 700 R, such as mineral lubricating oils obtained from crudes rich in aromatics. Particularly preferred are aromatics obtained by the solvent treatment of petroleum distillates having a Saybolt Universal Viscosity of between about 20 and about 200 at 210 F.

Table A gives properties of typical petroleum distillates useful for the extraction of aromatic fractions which are to be subsequently oxidized and used as an additive in accordance with the present invention.

blowing air through a grease composition con- TABLE A Properties of petroleum distillate sources Range of Sample A B C D E products Viscosity, SUS at 210 60 39.5 50.3 70.5 158 20200 Aniline point, F -i- Viscosity index 53 90 90 95 92 l00 to +100 Average molecular weight. 364 225-650 Flash, F l 445 500 570 350600 Percent aromatics 15 9 12 2-25 Instead of using the entire aromatic component as obtained from a petroleum distillate in the manner described above, the nitrogen or sulfur containing heterocyclic fraction thereof, such as the nitrogenous bases, can also be utilized. The nitrogenous fractions thus obtained consist of mixtures of compounds of carbon, hydrogen and nitrogen, and are probably such compounds as substituted pyridine, quinoline, piperidine, indole, carbazole, pyrazine, cinnoline, naphthyridine, and homologues thereof. Also, the sulfurtaining an Edeleanu extract during its manufacture. Obviously, oxygen or any oxygen-containing fluid may be used in lieu of air. Also, chemical oxidation may be resorted to.

If the aromatic distillates or fractions thereof are oxidized prior to their addition to a grease, they may be oxidized by blowing with an oxidizing gas, such as air, air enriched with oxygen, pure oxygen, hydrogen peroxide, manganese dioxide, permanganates, chlorates, perchlorates, perborates, chromates, chromic acid, etc., preferably under conditions that do not cause the formation of organic peroxides.

Table C presents the properties of several typical oxidized aromatic fractions together with the conditions of oxidation. It will be understood that Table C gives the properties of arcmatic fractions which have been oxidized prior to their incorporation in grease compositions. However, when the same aromatic fractions are first incorporated in greases or grease forming components and later subjected to oxidation, substantially the same end products are formed.

TABLE C Preparation and properties of oxzdzzed aromatzc fractions Range of Sample A B C products Source Furiural extract of bulk 615- S02 extract of bulk distillate, Duo-Sol extract of a bulk distillate, 200 SUS at 210 F. 100 SUS at 210 F. tillatc. Air blowing conditions:

Time, hours 4.4 4.7 5.9 0, 5-8 Temp, F 430 430 300-500 Oxidation during grease for- 175410 matlon, temp, F. Properties of blown product: 045 0.45 0.30 0. 5. 0

Acidnumber (mg KOH/g). Approx. percent hydrocarbons:

Oxidized 1% 1 0.7% 0. 525. 0 Flash, F 400-600 Softening point, F--. 0-200 ous fractions which may be present in the aromatic fractions obtained from petroleum distillates by the Edeleanu process or the like may be used as additives in grease compositions of this invention, such as substituted thiophene, benzothiophene, dibenzothiophene, and homologues thereof.

Table B below gives the properties of suitable The above aromatic distillates and fractions and/or derivatives thereof may be oxidized by any suitable means either prior to or during their addition to a grease composition. Thus a preoxidized Edeleanu extract may be added to a grease composition during the process of making the grease or after the grease has been made, or an Edeleanu extra-ct can be added to a grease composition during some appropriate stage of its manufacture and oxidized therein. This may be accomplished by simply exposing to the air or The amount of oxidized products of this invention which can be used as an additive may vary over wide limits and depends upon various factors, such as the lubricant base used to form the grease, the amount and type of soap and other thickening agents used, and the like. Generally, the amount of oxidized product used varies from about 1% to about 20%, and preferably from about 4% to about 10%, of the total composition.

The soap used to make reases of this invention (which must contain the oxidized product as described above) may be made by saponification of various fats, fatty acids, derivatives of fats and oils such as fatty acids derived from vegetable, animal, marine and fish oils, and hydrogenated fatty acids thereof, preferably containing from 8 to carbon atoms, synthetic fatty acids produced from hydrocarbons such as oxidizing petroleum products which-may be either natural or synthetic, naphthenic acids, rosin acids, tall oil acids, as well as acids of the above type which contain substituent polar groups such as hydroxy, keto, halogen, amino groups and the like. Free glycerine in small amounts up to about 1% may be present in these acid products.

Specifically, the natural fats and fatty acid materials derived therefrom which can be used to form soaps include:

I. AnimaZ.-Tallow (beef, mutton, goat) etc., lard oil, bone oil, neats-foot oil, wool fat, horse fat oil, etc.

11. Vegetable oiZs.-Castor oil, cashew nut oil, peanut oil, cocoanut oil, jojoba seed oil, olive oil,

palm oil;. corn oil, cottonseedi oil, rapeseed. oil, Ravison oil sesame oil; soybean oil', linseed. oil, etc.

III. Marineand fish.0iZs.--Codfish. oi'li codliver oil, dog fish oil; dolphin oil, herring: oi1j,.Menhaden oil, porpoise oil, salmon oil, sardineoil, seal. oil, shark oil, whale oil, etc;

IV. Hydrogenated residuum or distillate fractions obtained from any of the oils. listed. above.

V; Specific fatty acids which can be used to form the soap may include saturated alkyl; monocarboxylic acids: Capric, undecyli'c, lauri'c, myris tic, palmitic, stearic, archadic, linoceric, mon tanic, mel'istic acids, etc.

V(a-) Unsaturated aZZcg/l' monocarboxylic acids. -Oleic, linoleic; erucic, clupanodonic, linolenic, brassidic, elaidic, elacostearic, stearoleicacids, etc.

V(b) Hydrozry aZIc'yZ' carbo-znyZ-ic acids-;-Di-- methyl hydroxy capryi'ic, dimethyl hyd'roxy capric, rici'noleic, rici'nolaidic, l2-hyd roxy stearic, 10,11-dihydroxy stearic acid, 4-hydroxy pal-mitic acid, linusic, sativic, lanocerie, dihydroxy behenic acids, etc. The preferred hydroxy fatty'acidsare those in which the hydroxy group is at least 12 carbon atoms removed from the ea-rboxyl group.

We) Keto acids.Licanic; 12-keto stearic, l3- keto behenic, jojoba oil fatty acids, etc;

VI. Miscellaneous acid-s.Acids produced by oxidation of hydrocarbons, e. g; parafiin wax, mercapto oleic acid, mercapto stearic acid, amino fatty acids, etc.

Mixtures of fatty materials and: derivatives thereof may be usedtoform soap. Thus. an ex"- cellentsoap for grease composition maybe made ample from about 0% of a hydroxy fatty acid and 90% hydrogenated fatty oil and/or; its fatty acid derivatives to about 90% of ahydroxy fatty acid and hydrogenated fatty oil product. When using hydroxy fatty acids in a mixture of fatty materials it is preferable tokeep the hydroxy fatty acids inthe range of between about 50% to 90%v by weight. The proportions. used are governed in part by the type of mineral oil base used for compounding the greases as. well as its intended. use.

The soap may be made by saponifying the above type fatty materials, their mixtures, with. metal oxide, hydroxides, carbonates, etc, or in the presence of several metal compounds, or. organic bases- A. Metals selected from the Beriodic Tableetg, Group Ilithiu.m, sodium, potassium, rubidium,

cesium.

Group II-calcium, strontium, barium,,beryllium,

magnesium, zinc, cadmium.

Group IIIal'uminum, gallium, indium.

Group IVzirconium, tin, lead.

Group Vbismuth.

Group VIchromium,

Group. VII-manganese..

Group VIII-iron, cobalt, nickel.

B. Organic bases such as organic nitrogen bases, e. g cyclohexylamine, trimethyl cyclohexylamine, ethanolamine, dodeoyla-mine, amyl hexylamine, dicyclohexylamine, triamylamine, quaternary ammonium bases, etc.

Greases prepared from. the fatty acid soaps of the alkali or alkaline earth metals, e. g. sodium, lithium, calcium, barium, strontium, and magnesium and their; mixtures, as well. as. the: alumi- 6. num and. zinc: soap greases;v are. particularly: in. hibitedi against: bleeding and age-hardening: by; addition thereto. of the oxidized products: of this. invention.

Instead of making: a soap, pre-made. soaps. can be=used to. form the. grease.

The lubricating oil used for compounding grease of'this invention. maybe. of wide viscosity range varying from about 150 Saybolt Universal: Viscosity at 100' F; to about 2000 Saybolt Universal Viscosity at 100 F. The viscosity indexof the oil can vary from below. zero. to. about I00 and have. an average molecular weight. ranging; from about 250 to 600. It may be highly refined and solvent treated by any known means. A preferred mineral oil is one which has avi'scosity between about 300. to 700 SUS' at 100- F., a viscosity index of from about 40 to '70. and an average. molecular weight of between about 350. and 550'.

Instead. of using straight mineral oil as the base, synthetic oils and lubricantsmay be substituted. in: part or wholly: for the mineral oil. Among the synthetic lubricants which can beused are: Polymerized olefins; organic esters, e. g. 21-ethylhexyl. seb'acate, dioctyl phthalate, trioctyl phosphate, polymeric tetrahydrofuran, silicones, etc. Under some: conditions of lubrication minor amounts of a fixed oil, such as castor oil, lard oil and the. like, may be admixed with the hydrocarbon oil and/or. synthetic oil used in makin a greasev composition of this invention.

In. accordance with thepresent invention the oxidized highly aromatic compounds and/or their derivatives can be added to-or prepared in the grease at anytime during orafter the cooking operation. If other additives are to be added they can also be added at any suitable time before, during or after the oxidized highly aromatic additive and/or its derivatives has been added to the grease.

Highly desirable greases may be prepared by using formulation within the following range:

General" Preferred range I range Percent Percent 5-25 Soap oxidized'products of this invention.

. 4,-10. Polyalkylene glycol and/or its derivativ 0-1 0. 01-0.,1 Hydrocarbon oil (viscosity l502,000 SUS at Grease compositions of this invention may be made inv the following manner using as an example the, following components:

Components Lb./l00lb'. grease The acids. and glycerides areme-lted with about twice their weight-of. oilatabout: C. and caustic solution is added. The precipitated soap is vigorously stirred toform a. slurry and heated to drive off. the. water... During the heating and stirring, a, modicum of polymeric silicone, e. g., dimethyl' silicone polymer, can be added to inhibit, foaming. Heating is continued with efficient stirring until a temperature of; about; 3.40? F. is reached. At this point. hot. oil. (250f-E.) con.-

taining oxidized Edeleanu extract is slowly blended in with the oil-soap slurry and the entire mixture is heated so as to maintain the soapoil mixture in a gelatinous state. If the Edeleanu extract is not oxidized prior to its addition to the soap-like mixture, the entire mixture should be exposed to the atmosphere so that the Edeleanu extract can be oxidized while the grease is being formed. The polyethylene glycol is usually added during the addition of the hot oil to the soap-oil mixture. The final mixture is heated to about 360 F. but below about 410 F. and then transferred to a suitable container for heat conditioning.

To illustrate the profound effect oxidized Q Edeleanu extract and non-oxidized Edeleanu extract has on the age-hardening of a grease the following experiment was made, the results of which are noted in the table below and plotted in the figure. One sample of a sodium soap grease, as described above, was prepared in an open kettle so as to allow the Edeleanu extract to become oxidized, and the other sample of a sodium soap grease containing the same materials was prepared in an atmosphere of nitrogen gas so as to prevent oxidation of the Edeleanu extract. As the figure shows, the two greases were tested periodically during storage after their preparation. According to the figure, after an initial 2 weeks period of equal hardening, the rate of hardening of the grease containing oxidized extract (see Curve A) suddenly retarded, while the grease containing unaltered extract (see Curve B) continued to harden at its original high rate.

Age hardening of soda-base grease Grease compositions of this invention may be prepared by any other suitable means known in the art and cooled either slowly or rapidly depending upon the type of soap used to make the grease. Thus, if soda soap or alkaline earth greases are made they may be cooled slowly in the kettle, whereas if lithium or aluminum soap greases of this invention are made it is preferred that they be cooled uniformly and rapidly either in tubes of small diameter or in thin layers by feeding the hot grease onto a steel belt andsubjecting the grease to a current of air or other cooling medium, so as to cool the grease in a, uniform fashion free from shearing stresses.

Additional stabilizing agents may be incorporated in these greases. A particularlydesira ble type of stabilizing agent which can be used with grease compositions of this invention includes the alkylene glycol and/or allgrlene thio glycol polymers as well as their mono-esters and ether polymeric derivatives. The alkylene glycol polymeric materials can be represented by the following general structural formula:

I. HO(CnH2n-OCmH2m) aOH wherein m and n and a are integers. Preferably the polymeric alkylene glycols as represented by the above general formula should be such that the factor at times the number of carbon atoms within the brackets should be at least 6 and more.

The polymeric alkylene glycols can be made by polymerizing in the presence of a catalyst such as iodine, hydriodic acid and the like, ethylene, propylene, isobutylene, n-butylene oxides and/or their mixtures. Such polymers can also be produced by reacting a monohydric alcohol with an alkylene oxide. Thus, a suitable product can be made by reacting n-butanol with propylene oxide at between about 212 to 230 F. under pressure and in the presence of an alkali catalyst.

The polymerized higher polyalkylene glycols having between 2 and 6 carbon atoms in the alkylene group are most effective as additives of this invention and those containing the ethylene and propylene groups are preferred. The average molecular weight of the polyalkylene glycols may be from about 200 to about 7000 and the preferred molecular weight being from about 1000 to 6000.

It is desired to point out that the higher polyalkylene glycols are composed of mixtures of several polymers, for example, a polyethylene glycol having an average molecular weight of 400 consists of various glycols varying from a minor amount of monoethylene glycol and increasing up to the pentadecaethylene glycol. Therefore, it is the average molecular weight which is specified and where in the present specification polyalkylene glycols or polyethylene glycols are referred to, they define the higher glycols having an average molecular weight in excess of 200 and preferably in excess of 400, those with an average molecular weight of between about 1000 to 1500 being very effective in carrying out the present invention.

In lieu of the polyalkylene glycols, the ester and ether derivatives can be used. The esters can be made from a variety of acids having between 2 to about 22 carbon atoms and preferably between about 10 to 18 carbon atoms. Acids which may be used are the aliphatic, aromatic, cyclic, sulfonic acids and the like. Fatty acids and especially the higher fatty acids are preferred and include such acids as lauric, myristic, palmitic, stearic, arachidic, behenic, oleic, ricinoleic, hydroxy steario, phenylacetic, phenyl stearic acids and the like. However, such acids as naphthenic acid, oil-soluble petroleum sulfonic acids, tall oil fatty acids, aromatic acids, e. g. salicylic and phthalic acids and the like may be used to form the esters. Specific examples of esters of this type are the polyethylene glycol monostearate, polyethylene glycol monooleate and the like.

Ether derivatives of polyalkylene glycols may be made by any conventional method and the aromatic ethers of polyalkylene glycols having the general formula:

wherein m, n and r are integers and R is an organic radical, preferably a. hydrocarbon. These '9 materials can be preparedby reactingaan-alkylene glycol .or an alkylene oxide with .an valkylene .sulfide, e. g. ethylene, propylene, amylene sulfides, .thio glycol .or mercaptans.

The average molecular weight of the polyalkylene glycol derivatives can be below .400 and u to about 7000, the derivatives having an average molecular weight of between 700 to about 7000 are referred.

.The amount of ,polyalkylene lglycol derivatives thereof or other anti-bleeding agent which can .be used depends upon the-soap concentrationand inpart upon the type of oil base used. .I-IoweVel;, it has been found that it isnot necessary to use more than 1% by weight of these additives ;although larger amounts can .be .used if desired. Generally effective results are obtained with .concentrations ranging from 0.01 toabout 0.5% and preferably when kept within thegrange of between about 0.05 to about 0.25% by weight.

To further illustrate the present invention the following example is presented.

In a suitable open grease-making l'kettle approximately 3.7% of hydrogenated fish voil fatty .acids and 3.7% of hydrogenated castor .oiliatty acids, 1.0% lithium hydrate .solution and about of a 100 SUS at 100 F. parafiin oil .can be admixed and heated while stirring to a temperature of between about 380;and about 400 F. To this mixture about v35 .to 40% of :100 SIIS at 100 paraifin .oil, 30% .2000 ,SUS .at 100 1?. Coastal Pale Oil and about.5% ;to.l5% .of oxidized Edeleanu extract derived .from a 16.0 .8158 210.F. bulk distillate is added very slowly and the :tem-

perature of the mixture maintained at .between about-380 to 385 F. When a homogeneous mass is formed about 0.01% polyethylene glycol 'is added to thegrease. The .hot fluid mass can the .ponredinto flat pans .to .a depth of less than 1 inch and exposed to a current .of cooling .air so that the grease cools down :to around about 150 F. inless than SOminutes. .The cooledgrease forms an improved non-bleeding lithium soap grease upon milling. The oxidized .Edeleann extract to be used in this test may be obtained byair blowing the extract at :a temperature of about 425 F. for about 4 hours.

.The process of making the above grease was repeated except that the oxidized .Edeleanu extract was omitted.

The above lithium :soap greases were tested for bleeding .in ccordance with the Army-Navy Aeronautical specification for-greases -AN-G-25 of April 10, .1946. The sample containing oxidized Edeleanu .extract showed .no tendency toward bleeding while the sample .from which oxidized Edeleanu extract was omitted showed marked tendency towards .bleeding.

During the cooking of the above lithium grease, there may be introduced small amounts of soaps or salts, generally in amounts of less than 2% for :additonal benefits. .For example, there may be incorporated into a lithium soap grease, as described above, a minor amount of aluminum-or sodium soap -or alkali and alkaline earth naphthenates, .acetates, etc.

Minor amounts of oxidation inhibitors can be added to grease compositions of this invention such as N-butyl paraphenylene diam'ine. Also efiectiveas oxidation inhibitors are a'lpha -or beta naphthylamine, phenyl-alpha or beta naphthylamine, alpha-alpha, beta-beta, or alphabeta dinaphthylamine, diphenylamine, tetramethyl diamino diphenylmethane, "petroleum alkyl phenols, and 2,4-ditertiary butyl 6-meth yl"-pheno'l.-

Corrosion inhibitors which are articularly 10 applicable with pomposrtions of this invention are .N-prima-ry :amines containing 1210.163151] :6 .and more than .18 carbon .atoms in themolecule such as hex-ylamine, octylamine, :decylamine, .dodecylamine, octaoecylamlne,.heterocyclicnitrogen containing organic compounds such as alkylsubstituted oxazolines and 'oxazole salts of :fatty acids.

Extreme pressure agents can be added tosuch grease and the preterred agents comprise esters of phosphorus acids such as tri-aryl, alnylhyoroxy, .ary-l, or aralkyl phosphates, thlophosphates or phosphites, etc., neutral aromatic sulfur compounds such as diaryl sulfides and polysulfides, e. ,g.-di,.hen yl sulfide, dlcresol sulfide, dioenzyl sulfide, methyl 'butyl :diphenol sulfide, etc., diphenyl selemoeandoiselenloe, dicresol selenide and polyselenide, etc., .suh'urized fatty oils or esters :of -fatty;acids and monohydric alcohols, e. g. sperm oil, jojoba oil, etc., in which the sulfur is tightly bound; ,sulfurized .long-zchainolefins obtained by dehydrogenation or cracking of wax; sulfurized phos horized :fatty oils, acids, esters and ketones, phosphorus acid esters having sulfurized organic radicals,.such as esters'of phosphoric or phosphorus acids with hydroxyiatty-aeius, .chlorinated hydrocarbons such ;as ichlorinatedjpa-raffins, aromatic hydrocarbons, terpenes, mlneral lubricating oils, .etc.; or chlorinated esters of fatty acids containing the chlorine in positions other than the alpha position.

Additional ingredients which can be added are anti-wear agents .such as oil-soluble urea or thio-urea derivatives, e. g. urethanes, allophanates, zcarbazides, .carbazones, etc. or rubber, .polyisobutylene, polyvinyl esters, etc.; V1 improvers :such as :polyisobutylene having a molecular weight above about 800, voltolized parafiin wax, unsaturated polymerized esters of fatty acids and .monohgydric alcohols, etc.,; oiliness agents such as stearic andoleic acids and pour pointzdepressors such as chlorinated naphthalene toiurther lower the pour point of the lubricant.

Theamount of the above additives can .beadded toigrease .compositionszofathis invention in around about 0.01% to ,less than 10% by weight and preferably 0.1 to 5.0 .by weight.

Greases of this invention are applicable for general automotive uses, and are excellent aircraft-greases, industrial greases land the like.

.This case is .;a continuation-in-part {of the copending application, Serial No. 40,727 filed July 26., 1948, .now abandoned.

.I claim as my invention:

1. .A lubricating grease comprising .a major amount of a mineral lubricating 'oil having .a viscosity index oftrom 40 to 70, about 5% to 25% of asodasoap of ahigher fatty acid, from0.01 to 0.1% of polyethyleneglycol having an average molecular weight of 600, andirom 4% to 10% of an oxidized petroleum aromatic extract traction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SIIS at 210 EL, said aromatic extract fraction having an aniline point between 25 and 20., and said oxidized petroleum fraction having been formed by exposure of the fraction and the :grease forming components to air during grease forming operations at a temperature between about F. and about 410 F.

2. A lubricating grease comprising a major amount of a mineral lubricating oil having a viscosity index of from 40 to 70, about 5% to 25% of a lithium soap of .a higher fatty acid, .from 0.01% to 0.1% of polyethylene :glycol having an average molecular weight of1'600, and from 4% to 10% of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 C. and said oxidized petroleum fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F.

3. A lubricating grease comprising a major amount of a mineral lubricating oil having a viscosity index of from 40 to 70, about to 25% of a lithium soap of a mixture of hydrogenated fish oil acids and hydrogenated castor oil, from 0.01% to 0.1% of polyethylene glycol having an average molecular weight of 600, and from 4% to of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 F., and said oxidized petroleum fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F.

4. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a soap to thicken the oil, and from about 1% to about 20% by weight of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 C., said oxidized solvent fraction having been iormed by exposure of the fraction anu the grease forming com onents to air during grease forming operations at a temperature between about 175 F. and about 410 F.

5. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a soda soap to thicken the oil and a minor amount of from about 1% to about 20% sumcient to prevent agehardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 C., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F.

6. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a lithium soap to thicken the oil and a minor amount of from about 1% to about 20% sufficient to prevent age-hardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 C., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F.

7. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of an aluminum soap to thicken the oil and a minor amount of from about 1% to about 20% sufficient to prevent age-hardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and C., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about F. and about 410 F.

8. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a soap to thicken the oil and a minor amount of from about 1% to about 20% suflicient to prevent agehardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 $03 at 210 F., said aromatic extract fraction having an aniline point between 25 and 7 5 C., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F., and a minor amount, but less than 1 of a polyalkylene glycol having an average molecular weight 01 between about 400 to about 7000.

9. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a soda soap to thicken the oil and a minor amount of from about 1% to about 20% sufficient to prevent agehardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 R, said aromatic extract fraction having an aniline point between 25 and 75 C., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F., and a minor amount, but less than about 1% of a polyalkylene glycol having an average molecular weight of between about 400 to about 7000.

10. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a lithium soap to thicken the oil and a minor amount of from about 1% to about 20% sutficient to prevent age-hardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 0., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 and about 410 F., and a minor amount, but less than about 1% of a polyalkylene glycol having an average molecular weight of between about 400 to about 7000.

11. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of an aluminum soap to thicken the oil and a minor amount of from about 1% to about 20% sufi'lcient to prevent age-hardening of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of 60 SUS at 210 F. said oxidized petroleum aromatic extract fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between 13 about 175 F. and about 410 F., and a minor amount, but less than about 1% of a polyalkylene glycol having an average molecular Weight of between about 400 to about 7000.

12. A lubricating grease comprising a major amount of a lubricating oil having a viscosity index greater than about 40, and a minor amount of a soap and from about 1% to about by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about and about 75 C., and said oxidized fraction having been formed by exposure of said fraction to an oxygen containing gas at a temperature between about 175 and about 500 F.

13. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than about 40, and a minor amount of a soap and from about 1% to about 20% by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about 25 and about 75 C., and said oxidized fraction having been formed by exposure of said fraction to an oxygen containing gas at a temperature between about 300 and about 500 F. prior to incorporation in the grease.

14. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than about 40, and a minor amount of a soap and from about 1% to about 20% by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about 25 and about 75 C., and said oxidized fraction having been formed by exposure of said fraction to an oxygen containing gas at a temperature between about 300 and about 500 F. prior to incorporation in the grease for a period between about 0.5 and about 8 hours.

15. A lubricating grease comprising a major amount of a mineral lubricating oil having a viscosity index of at least 40, a minor amount of a soap and from about 1% to about 20% by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about 25 and about 75 C., and said oxidized fraction having an acid number between about 0.25 and 5.0 mg. KOH per gram and having between about 0.5 and about 25% of its molecules in an oxidized state.

16. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than about 40, less than about 1% of a polyalkylene glycol having an average molecular weight between about 400 and about 7,000, and a minor amount of a soap and from about 1% to about 20% by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about 25 and about 75 C., and said oxidized fraction having been formed by exposure of said fraction to an oxygen containing gas at a temperature between about 300 and about 500 F. prior to incorporation in the grease for a period between about 0.5 and about 8 hours.

17. A lubricating grease comprising a major amount of a lubricating oil having a viscosity index greater than about 40, and a minor amount of a metallic soap of a higher aliphatic monocarboxylic acid and from about 1% to about 20% by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about 25 and about 75 0., and said oxidized fraction having been formed by exposure of said fraction to an oxygen containing gas at a temperature between about and about 500 F.

18. A lubricating grease comprising a major amount of a lubricating oil having a viscosity index greater than about 40, and a minor amount of an alkali metal soap of a higher fatty acid and from about 1% to about 20% by weight of the grease of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between about 25 and about 75 C., and said oxidized fraction having been formed by exposure of said fraction to an oxygen containing gas at a temperature between about 175 and about 500 F.

19. A lubricating grease comprising a major amount of a mineral oil having a viscosity index greater than 40, a minor amount of a soap to thicken the oil, and from about 1% to about 20% by weight of an oxidized petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 C., said oxidized solvent fraction having been formed by exposure of the fraction and the grease forming components to air during grease forming operations at a temperature between about 175 F. and about 410 F.

20. The process which comprises forming a mixture of a lubricating oil having a viscosity index greater than 40, a minor amount of a soap to thicken the oil and from about 1% to about 20% by weight of a petroleum aromatic extract fraction obtained by solvent treatment of a petroleum distillate having a viscosity of from about 20 to about 200 SUS at 210 F., said aromatic extract fraction having an aniline point between 25 and 75 C., and exposing the mixture to air during grease forming operations at a temperature between about 175 F. and about 410 F. whereby said aromatic extract fraction is oxidized.

ROBERT J. MOQRE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,971,750 Kaufman Aug. 28, 1934 2,057,473 Burch Oct. 13, 1936 2,128,574 Van Peski Aug. 30, 1938 2,245,772 Gothard et al June 17, 1941 2,326,596 Zimmer et a1 Aug. 10, 1943 2,343,125 Larsen Feb. 29, 1944 2,403,104 Lien July 2, 1946 2,445,935 Bo i awn-"u".- July 27, 1948 

4. A LUBRICATING GREASE COMPRISING A MAJOR AMOUNT OF A MINERAL OIL HAVING A VISCOSITY INDEX GREATER THAN 40, A MINOR AMOUNT OF A SOAP TO THICKEN THE OIL, AND FROM ABOUT 1% TO ABOUT 20% BY WEIGHT OF AN OXIDIZED PETROLEUM AROMATIC EXTRACT FRACTION OBTAINED BY SOLVENT TREATMENT OF A PETROLEUM DISTILLATE HAVING A VISCOSITY OF 60 SUS AT 210* F., SAID AROMATIC EXTRACT FRACTION HAVING AN ANILINE POINT BETWEEN 25 AND 75* C., SAID OXIDIZED SOLVENT FRACTION HAVING BEEN FORMED BY EXPOSURE OF THE FRACTION AND THE GREASE FORMING COMPONENTS TO AIR DURING GREASE FORMING OPERATIONS AT A TEMPERATURE BETWEEN ABOUT 175* F. AND ABOUT 410* F. 